Socio-economic and technical dimensions of integrated pest management

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Zenaida F. Toquero

Pest control has gone through an evolution from the sixties where emphasis was on the use of chemicals as the best technical option against pests, to the eighties where the thrust is on judicious, needbased use of pesticides (rather than the commonly adopted practice of calendar-based prophylactic spraying) that integrates biological, cultural, and chemical control methods. (Panganiban and Sumangil, 1983, Martin, 1988). This new pest control concept, referred to as Integrated Pest Management or IPM has been stimulated by the intensification and increasing complexity of crop protection problems, coupled with the associated environmental, financial, and health hazards of heavy chemical use.

Kenmore (1987), defined the meaning of integrated pest management as follows:

....."lt's INTEGRATED because it tries to reassemble into one unit the best mix of pest controls for a particular field in a particular season or time. The glue that holds these controls together in an integrated system is the natural population control ecology of the community of species that live in the field. Natural forces which include biochemical immunity (coconut diseases never attack rice) habitat invulnerability (more than 99% of the world's weeds can never live in flooded conditions along with rice) and carnivory (more than 99% of plantfeeding insects found in rice fields are killed by predators, parasitoids, or pathogens before they grow up) keep more than 99% of pests under control 100% of the time......

.....PESTS means any species that eats the crops and prevents farmers from reaching their goals for a particular crop. Pest may include weeds, rodents, insects, fungi, bacteria, viruses, nematodes, birds and mycoplasms. A species becomes a pest only if it eats too much of that crop or commodity which reduces yield from its agronomic potential......

.....MANAGEMENT means the set of skills ... to be learned and practiced.

.....INTEGRATED PEST MANAGEMENT, therefore, is a set of skills that enable farmers, users, of practitioners to recognize which of the few populations out of the many in their fields or warehouses are likely to become pests. IPM then gives these users a large selection of control tactics from which they can choose the best mix of pest controls without necessarily involving use of more pesticides "

In the context of the associated environment and the population dynamics of the pest species, IPM utilizes all suitable techniques and methods in as compatible a manner as possible to maintain the pest population at levels below those causing economic injury (FAO, 1967). This means the rational use of all techniques in suppressing pest population through such measures as biological control, genetic techniques, host plant resistance, and cultural, mechanical and chemical controls. It is an effort to bring together multidisciplinary methodologies in developing agroceosystem management strategies and decision-making tools that are workable and economically feasible, ecologically sound, and socially acceptable (Kenmore, 1983; Litsinger, 1984; Adalla, 1988).

Technical Dimensions of IPM

Pesticides are scarce commodities whose life spans must be maximized to ensure that they are available for continued use, if so desired, within the integrated pest management programmes. Insecticide residues decay over a wide range of temperature and grain moisture contents, thus the need to determine these (data to allow for; (a) accurate prediction of the amount of pesticide needed for a specific crop or commodity; (b) avoidance of under- or over-dosing; and (c) possible definition of residue tolerances.

Insect/Pest Biology

A major problem in insect/pest control is the lack of knowledge of pest biology and the factors causing physical loss and quality deterioration of grains in storage. Correct identification/ recognition, of the various pests, their life cycle and behavior patterns have a considerable bearing on the inspection methods and timing of control application for more effective results. For instance, some egg-laying species like the grain weevils, lesser grain borers and the grain moths, initiate their infestation and damage to the grain by leaving their eggs on the unharvested grain in the field. These eggs then mature and become adults when these infested grains are already in storage causing the most damage.

It is, therefore important to have a knowledge of pest biology because different species require different strategies of control at the various stages of their life cycle. Some storage pests are much less dangerous than others and may not necessarily require immediate pest control. Conversely, others are highly destructive, thus the need for immediate control measures becomes imperative.

Biological control

Another major issue about chemical pest control is the propensity of some pests to develop resistance to pesticides through time. The problem is further aggravated by the limited number of chemical classes of pesticides/insecticide available, and its continuing soaring prices. One possible solution to these problems is the use of biological control measures such as parasites and predators (see Appendix Table 1) and disease organisms or pathogens such as various subtypes of the bacterium, Bacillus thuringiensis amoebae and sporozoans such as Triboliocystis garnbami, Mattesia trogoderma and other species, Nosema spp., Halics spp., which are most frequently encountered in dense populations of insects and can cause high mortality (Semple, 1985). None of these are known to infect man and therefore offer considerable potential for use in biological control.

The use of various botanical insecticides is another cheap pest control method in paddy storage. One good example is the neem plant (Azadirachata indica A. Juss, Meliaceae) which was found to inhibit insect population buildup, primarily Sitophilus oryzee and Rhizopertha dominica after three months of storage (Muda, 1984). The repellant effect of the volatile, biologically active ingredient in neem, such as azadirachtin and melianatrol has been evaluated, the former of which possesses known antifeedant properties against R. dominica (Malik and Muttaba, 1984). Neem leaves or seed in powder form had been previously studied to show long persistency with proven effectiveness against S. oryzee, R. dominica, and Trogoderma granarium in wheat for nine to twelve months of storage (Jilani, 1984). Neem can therefore be a cheap alternative to synthetic insecticides, with potential adaptation for large scale use. Extracts from black pepper have bee evaluated in the Philippines (Morallo-Rejesus, 1983) and other vegetable oils such as palm oil, bran oil, peanut of,, and corn oil at 5-15 ml/kg have provided insect control for four months on legume seed without affecting seed viability (Suprakarn and Tauthong, 1981).

Several studies have likewise looked into the issue of varietal resistance as a possible pest control measure. One of these is the study done by Rejesus and Dimaano (1984) on the resistance of 20 varieties of milled rice to corn weevil (S. zeamais) and red flour beetle (T. castaneum). The study showed that IR36 and IR32 are highly resistant to corn weevil and red flour beetle respectively. Varieties such as IR29, IR38, IR42, IR43, IR46 and IR5853 were highly susceptible to T. castaneum. These results indicate that insects preferred some varieties for feeding because in some cases, these varieties are suitable for the insects' survival and development. The varieties' chemical composition (such as percent amylose content which was positively correlated to index of susceptibility) may likewise explain degree of proference.

Effective Loss Assessment

According to Hodges, et.al. (1984), there had been virtually no scientific evaluation of the methods used in the detection of insect infestation or the interpretation of results that are obtained therefrom. From what is currently known about distribution and behavior of insect pests in grain stores, it seems that the levels of infestation are very likely to be inaccurately reported. As a result, expensive control procedures such as insecticide spraying and fumigation may often be applied either too early or too late so that the maximum benefits are not realized.

Farmers usually spray insecticides during crop production when they perceive the need for it even when in most cases, the pest level is below the economic threshold level (ETL), And to think that total area coverage rather, than spot application, is often practiced one can imagine the waste of the whole exercise. Furthermore, this socalled economic threshold does not consider the population of beneficial organisms.

It is therefore very important that prior to any rational campaign againsts insects and pests in stored products there is an updated knowledge on the pest complex occuring in the warehouse, the relative importance of each species, products attacked and nature of damage, and the presence and abundance of the natural enemies of the identified pests. Such information will give an indication on changes in pest situation such as pest resurgence, shifts in pest dominance, and the causes of such altered conditions (Sabio, et. al., 1984). It is equally important to obtain reliable and fairly accurate estimates of grain losses caused by insects from which the ETL at which control measures (particularly fumigation) should be applied can be established. This information will aid in developing possible improvements in pest control strategies currently being utilized by applying them at a time that will economically justify their use.

Economic Dimensions of IPM

According to Norgaard (1976), there are three interrelated ways by which economics may enter into the design of IPM strategies: (a) the farmer's pest management goals are largely economic; (b) economics being a science of resource allocation can aid in selecting optimal quantities and combinations of pest management inputs; and (c) the adoption of new management practices can be speeded up through an economist's understanding of the incentives underlying farmer's behavior and the effect of alternative social institutions on these incentives.

Physical and Economic Environment of Affected Sectors

The ultimate pest management goal of a rational farmer, trader and/or miller/processor is to maximize profit (if he is market oriented) or to produce enough for his needs (if he is a subsistence farmer). This is done through selective reduction or increase of chemical use, selective use of pesticide with a more narrow action spectrum, and use of new biological and other control methods. This is where the importance of studying the socio-economic component of IPM technology is highlighted wherein farmers, traders and/or millers practice pest management strategies according to their resource capacity, their objectives, and their perception of pest attacks (Role and Ocampo, 1986). Their acceptance or rejection of the IPM technology will be partly conditioned by the physical and economic environment within which they operate and this includes the size or scale of their operation, access to capital, infrastructural support and services, etc.

The size or scale of a business operation (whether it be at the farm, traders or processor's level) largely determines the willingness (or the lack of it) of a potential adoptor or user to accept or use a give postproduction technology. In the case of rice producers, small-sized farms are generally on subsistence level that receptivity to new and/or improved technology such as IPM will be nil or totally lacking. As the size of his operation gets bigger and more of his produce is market-directed, his financial resources improves and he becomes more quantityand quality-conscious in order to avail of any price premium for such products. Thus, he may become more receptive to IPM. The same condition can be said of the traders and processors. As their volume of business expands, the more they tend to improve their facilities and management operation. They begin to be more conscious of the quantity and quality of product they procure and distribute to have a greater share of the rice market.

Risk and Uncertainty

Farmers living near subistence levels are commonly reported adverse to risk because a reduction in income, even for a relatively short period of time, could seriously affect the wellbeing of the farm family. When analyzing why potential adoptors and/or users do not adopt new techniques, the new technique must be measured against their needs as well as their capabilities. Surely these targeted beneficiaries have a right to be skeptical when proposed changes involved some financial outlay as compared to the total income that they might have, for something which is new or different from their regular practice or way of life. Moreover, those "improvements" might be too technical or too cumbersome or complicated for these potential users to fully comprehend and use. Thus, an understanding of the decision-making processes of farmers can help facilitate the adoption of certain pest management techniques. An understanding of this process and how farmers are influenced by their resource endowments, management skills and knowledge of marker factors can help explain potential constraints in the adoption of technology. Unless these constraints are identified and considered during technology development, the present generation of agricultural research scientists may again fail where their predecessors did; the technology they developed was so efficient and perfect, but it hardly conformed to basic realities and farmers' needs (Role and Ocampo, 1986).

Loss Assessment

In order to effectively estimate/verify the financial benefits of IPM, there is a need to accurately estimate as much as posible the postproduction losses (quantitative and qualitative) incurred due to pest infestation, the costs incurred due to this loss and the consequent costs of pesticides used under pure chemical control. This information is very important before any appropriate intervention procedure can be undertaken to elucidate where the major losses are being incurred within the system, the magnitude of such loss and the kind of strategy that is best suited for alleviating or improving the situation, both in terms of weight loss reduction and maintenance of quality. The importance of this exercise may not be as great at the farm level - where volume of grain stored is just sufficient for home consumption - as it is at the commercial and/or government level where big volumes of grains are being stored and handled for market.

Social Dimensions of IPM

Traditional Value System

According to Castillo (1965), the farmers are claimed to resist technological innovations because of their adherence to deeply rooted traditional patterns. But whether farmers are really to blame for the nonadoption is debatable. Decisions of farmers and/or potential adoptors-users are influenced not only by identifiable techno-economic factors but also sociocultural factors. Central to this problem is the value system. According to Rola and Ocampo (1986), traditional families are characterized by the stability of their value system. The essential feature of such is the complex web of agreed norms of behavior, a kind of cumulative common wisdom unconsciously accepted by everyone without need of visible proof. This complex web is often developed over hundreds of years and for this reason the society gives value to particular practices.

Decision-Making Process

Integrated pest management is a new concept of a people-oriented technology and its success or failure will depend on how the clientele group will perceive its benefits vis-a-vis their traditional farming practices on the one hand and possibly how change agents or technocrats relate the technology to its end users on the other hand (Adalla, 1988). IPM involves a lot of management decision-making which calls for serious efforts on the part of the extension agent in his tasks to equip and train the targeted clientele with the necessary technical expertise on which to base his decision. Because of the developed bias of farmers/users as regards pesticides as an important input in their production, farmers may initially look at IPM as a risk and will therefore hesitate to readily adopt it. Their hesitancy is further compounded by the new activities they have to undertake (which are necessary so that every IPM decision can be based on objective reality) which may be quite "foreign" and tedious to them. This includes: (a) regular visit/monitoring of pest population; (b) learning about "friendly" pests vs. real ones; (c) deciding whether or not immediate action is needed based on infestation levels they themselves have to determine; and (d) facing the consequence that pesticide application is not a sure guarantee of eliminating pest damage.

IPM offers changes in farming methods, hence, changes also in the farmer's way of life. Its introduction demands that farmers be provided not only with the material farm inputs, but also sets of decision-making tools; what resistant variety to use, when to use pesticides, what pesticides to use, etc. The IPM approach requires regular field monitoring, and farmers are encouraged to define what is the economic threshold level, without which judicious and economical use of pesticides will never be realized... The introduction of IPM, therefore, requires the adaptability of the approach not only to the natural environment and economic conditions but perhaps more importantly, to the attitudes, values, and perception of the small farmer.

Effective Extension and Delivery System

The mere existence of IPM technology is not enough. The introduction of IPM would be meaningless if it will not be transformed and repackaged to suit the farmer's needs. What is therefore needed is an effective extension mechanism, appropriate diffusion approaches and other information support services on crop protection to make the technology usable by the targeted clientele. These IPM approaches must be developed and modified and made compatible to the social system of small farmers. According to Stuart (1988), the verification of location specificity of IPM technology should be done with the active and wholehearted participation of farmer cooperators as "research partners." It should seek to enable the targeted users or practitioners to experience the research process by comparing the agronomic and economic performance of locally adapted IPM with the user's practices in paired-parcel trials within his own facilities. Because of the complexity of IPM, not only the farmer or potential adoptor should be involved in the training/extension process but the potential role of non-traditional IPM audiences such as women, children, and other members of the household or community should also be considered. Studies have shown that women generally take over the responsibility of on-farm storage so there's probably a need to redirect to these non-traditional sectors future training and extension programs. Moreover, since women can easily/conveniently relate to women extension workers better than the male, upgrading of these female extension agent's skills in this area need to be looked into. Based on IRRI records of IPM training program, out of the 171 Asian traineesas of 1987, only 17 were women. Whether or not there is a deliberate attempt to discriminate against women extension agents, the end result seems to indicate that the core of women extension agents has not been given equal chances as their male counteraprts, yet the expectations from them are the same.....

Ecological impact

According to Rola (1986), total reliance on chemical control in the past has proven to be a disastrous solution to the long-term problems of insect and other pests. Experiences from many parts of the world show that too much pesticide misuse and overuse create a host of other problems like insecticide resistance, pest resurgence, outbreaks of secondary pests, environmental contamination and increasing food residue levels (Table 1). These latter two problems affect the general population, not just the direct users but the indirect users as well. This is reflected in the available statistics on pesticide poisoning cases shown in Table 2. The table reflects the data gathered from government hospitals in 48 provinces for 1980-83 showing 659 total cases of acute pesticide poisoning in 1980, 633 in 1981, 238 in 1982 and 824 in 1983. There are no available statistics from rural doctors who routinely treat patients for occupation "sickness" during and after the main spraying season, so the above figuress are likely underestimated. About 60-71% of the cases were suicidal or non-agricultural related since most of these hospitals are located in the urban areas.

A recent study by Loevinsohn (1987) has indicated that in the major rice growing areas of the Philippines, widespread adoption of insecticides by small holder farmers appear to have resulted in an increase in mortality of 27 percent among economically active users as a result of pesticide misuse. This would imply an annual mortality of many tens of thousands in the rice growing areas across Asia whose farmers adopt similar practices. It also indicates that the commonly adopted figure of 10,000 deaths worldwide from accidental and occupational poisoning is understated. That the impact is among economically active men implies that the social or economic impact is greater than the undifferentiated number of deaths would suggest.

In terms of pesticide residue analysis, the accepted practice have always been to analyze the residues of harvested/milled crop at the market. The local marketing, however, does not allow for the disposal/rejection of produce due to high residue levels. Thus, even if residues found in food exceed the maximum residue limit set by FAO or even our own FPA guidelines, nothing is being done. With regard to our export grain, if they do not pass the quality control of the importing country, then the produce is dumped in our local market. For safety/health reasons, it is important that residue analyses be done at the farm level where, given a certain amount of pesticide being used, one could determine the corresponding residue based on a transformation function. There's likewise a research need that will relate toxicity levels and residue levels.

Table 1. Some possible side-effects of the production and use of pesticides.

1. Entrance and persistence of pesticides into different compartments of the environment, including the food chain.
2. Occupational hazards associated with chemicals with high biological activity.
3. Unintentional exposure of people as a result of careless spraying operations.
4. Careless transportation, storage, and destruction of pesticides and pesticide containers.
5. Mismanagement of dangerous wastes at the production plants.
6. Ecological effects, including development of resistance in disease vectors.

Source: Environmental Pollution Control in Relation to Development Report of a WHO Exper Committee, Technical Report Series 718, Geneva, 1985, p. 21.

Taken from Rola, A.C. 1986. Policy Recommendations for Pesticides. Center for Policy and Development Studies. Working Paper No. 86.03.

Table 2. Pesticide poisoning cases admitted to government hospitals according to chemical grouping, Philippines, 1980-1983.

Source of data: UP-PGH. Taken from Rola, A. C. 1986, Policy Recommendations for pesticides. Center for Policy and Development Studies. Working Paper No. 86.03.

There is also an urgent need to develop protective covering for farmers/users during pesticide application. Although pesticide companies have already developed protective clothing, they may find difficulty in selling them because of the psychological effects on the farmers/suers (i.e. it warns users that they're dealing with a hazardous substance). This may further discourage users from using that particular pesticide. Proper and strong extension programs should be undertaken to make possible farmers education and understanding of the proper use and handling of pesticides. Barangay nutritionists and health workers as well as village elders and other respected people in the community can be effective contact points for this extension/training programs.

BIBLIOGRAPHY

HAINES, C. P.1981. Paddy loss to insects. In GTZ Paddy deterioration in the humid tropics, a GASGA Seminar, 11-18 October, Bagulo, Philippines. pp. 67-76.

JILANI, G. 1984. Use of botanical materials for protection of stored foodgrains against insect pesta review. Presented at Research Planning Workshop on Botanical Pest Control Project, IRRI. Los Banos, Laguna, Philippines, 6-10 August 1984. 18 p.

KENMORE, P. E. 1987. IPM means the best mix. Rice IPM Newstetter. Vol.1, No. 1, July 1987. International Rice Research Institute.

MALIK, M. M. and S. H. Mujtaba, 1984. Screening for some indigenous plants as repellents or antifeedants or stored grain insercts. J. Stored Production Research. Vol. 20(1): 41-44.

MUDA, Rahim A.1984. Utilization of neem as a pest control agent for stored paddy. In Semple, R.L. and A. S. Frio, eds. Health and Ecology in Grain Postharvest Technology: Proceedings of the 7th ASEAN Technical Seminar, 21-24 August 1984, Kuala Lumpur, Malaysia. pp. 117-128.

REJESUS, B. M. and D. Dimaano. 1984. Some factors responsible for the varietal resistance of milled rice to Sitophilus Zeamais (Motsch) and Tribolium castaneum (Herbs"). In Semple, R.L. and A. A. Frio, eds. Health and Ecology in Grain Postharvest Technology: Proceedings of the 7th ASEAN technical Seminar, 21-24 August 1984, Kuala Lumpur, Malaysia, pp. 129-142.

SABIO, G. C. et al.1984. Establishment of economic threshhold level in stored grains and preliminary trial on methacrifos as stack spray. In Semple. R. L. and A. S. Frio, eds. Health and Ecology in Grain Postharvest Technology: Proceedings of the 7th ASEAN Technical Seminar, 21-24 August 1984, Kuala Lumput, Malaysia, pp. 65-93.

SAYABOC, P. D. et al. 1984. Rodent losses in commercial grain storage. In Semple, R.L. and A. S. Frio, eds. Health and Ecology in Grain Postharvest Technology: Proceedings of the 7th ASEAN Technical Seminar, 21-24 August 1984, Kuala Lumpur, Malaysia. pp. 101-115.

LITERATURE REVIEW

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CASTILLO, G. T. 1965. Towards understanding the Filipino farmers. Presented at a seminar, IRRI, Los Banos, Laguna.

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HODGES, R. J. et al. 1984. The assessment of methods of inspection for insects in bagged rice. In Semple, R. L. and A. S. Frio, eds., Health and Ecology in Grain Postharvest Technology: Proceedings of the 7th ASEAN Technical Seminar, 21-24 August 1984, Kuala Lumpur, Malaysia.

KENMORE, P. E., Eeong, K. L. and C. A. Putter. 1984. Political, social and perceptual aspects of integrated pest management programmes in Lee, B. S., Loke, W. H. and K. L. Heong. eds. Integrated Pest Management in Malaysia. Malaysian Plant Protection Society (MAPPS), Kuala Lumpur, Malaysia, pp. 47-66.

KENMORE, Peter E. Crop loss assessment in a practical integrated pest control programme for tropical Asian rice (no date). Mimeograph.

LOEVINSOHN, M. E.1987. Insecticide use and the increased mortality in rural Central Luzon, Philippines. The Lancet, June 13.

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OCAMPO. P. P. 1980. Adoption of recommended crop protection technology among rice farmers in Bulacan, Philippines. Unpublished M. S. Thesis, University of the Philippines at Los Banos.

PANGANIBAN, D. and J. P. Sumangil. 1985. Integrated pest control for Philipping rice farmers. Paper presented to the International Rice Commission 16th Session, IRRI, Los Banos, Laguna, Philippines.

ROLA, A. C. and P. P. Ocampo. The socioeconomic component of integrated pest management in FAO Proceedings of regional consultative workshop on integrated pest management, 17-21 June 1986, SEARCA, Los Banos, Laguna, Philippines. pp. 121-130.

DEMPLE, R. L. 1985. Pest control in grain storage systems in the ASEAN region. ASEAN Crops Postharvest Programme Technical Paper Series No. 1, Philippines. 77 p.

STUART, Teresa H. 1988. Operationalizing participatory development communication in an action research project on integrated pest management extension and women. Presented at the Women in Rice Farming Systems Training and Planning Workshop, IRRI, Los Banos, Laguna, Philippines, May 2,1988,17 p.

SUMANGIL, J. P.1984. The integrated pest control component of cost reducing technology for Masagana 99 in the Philippines. Paper presented at the Agritech 84 Conference, 9 September 1984. Manila, Philippines.

SUPRAKARN, C. and Tauthong. 1981. Stored products insect research in Thailand. In BIOTROP Special Bull. No. 9, "Pests of Stored Products", published by BIOTROP, Bogor, Indonesia: 77-86.

Appendix 1. List of parasites and predators positively identified in surveys conducted in ASEAN.

Taken from Semple, R.L.1985. Pest control in grain storage systems in the ASEAN region. ASEAN Crops Postharvest Programme Technical Paper Series No. 1, Philippines. 77 p.

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